This invention is directed to the field of compositions comprising natural product extracts for use in personal care products or pharmaceuticals.
Natural products and natural product extracts are often used in cosmetic and pharmaceutical applications. Natural products, particularly botanically sourced natural products, have demonstrable beneficial properties on the skin and hair. Extracts of these natural products have demonstrated antimicrobial, antiseptic, anti-inflammatory, antioxidant, enzyme stimulation or inhibition, pigmentation enhancement or control, photoprotective and many other physiological benefits.
Typically, the solvent systems used to produce these extracts are polar in nature, and most typically are water or glycols or a combination thereof. These polar solvents enable the extraction of only a similarly polar material from the biomass of the natural product material. Similarly, apolar solvents have been used to remove the apolar fractions from the biomass of the natural product materials. There is currently no single universal solvent capable of only extracting both the desired polar and apolar fractions. As a result, typical natural product extracts only provide a portion of the physiologically or aesthetically beneficial components.
It has not been possible to date to combine an aqueous extract with a lipid or other apolar phase into a single system without the use of surface active agents and special processing conditions to form emulsions or dispersions. Surface active agents permit the mixing of a hydrophilic phase and a hydrophobic phase by lowering the surface tension between the two phases, thereby creating micellar structures which, when mixed with a suitable processing procedure, produce stable systems. However, these surface active agents may be irritating to users, and the processes used to prepare the emulsions or dispersion make them difficult to reproduce.
Since many bioreactive or aesthetic components of the natural product are located within the structure of the cell wall or other organelles within the cell, a suitable process is required to extract the desired components from the cell. Simple solvent extraction is usually insufficient to remove the protected material from the cell. The cell wall barrier must be perturbed or ruptured sufficiently to allow diffusion to occur into the extracting solvent. A method is therefore needed to rupture cell walls and membranes to maximize the removal of the physiologically active or aesthetically pleasing materials. Examples of such process conditions include the use of heat, high shear mixing, ultrasonic waves, microwaves, high pressure and prolonged polar or apolar dialysis.
It is preferred to combine the process described above with the use of separate polar and apolar solvents to remove the maximum amount of all of the materials of interest. It is further preferred to combine both the polar and apolar extracts into a single, homogeneous preparation without the use of surface active agents which can cause irritation.
It is therefore an object of the present invention to provide an improved method of obtaining a composition comprising both the hydrophobic and hydrophilic components of a natural product or blend of natural products.
It is another object of the present invention to provide a single composition having both oil soluble and water soluble components of a natural product extract, in order to take advantage of synergy which is often associated with the use of multiple components of a natural product.
It is another object of the present invention to provide a greater functional activity due to the presence of a full complement of polar and apolar materials with physiologically beneficial or aesthetically pleasing properties.
It is another object of the present invention to provide a composition having greater potency and stability of the desired components, in comparison to prior art compositions.
It is another object of the present invention to provide better delivery of the physiologically beneficial active agents to sites within the skin or hair, where the active agents are needed for activity.
It is another object of the present invention to provide ease of manufacture of a finished system containing the full complement of extracts, yielding cost savings and greater reproducibility with consistent quality standards.
It is another object of the present invention to provide a greater versatility to compositions of natural product extracts that can be achieved by preparing prior art homogeneous or heterogeneous complexes.
It is another object of the present invention to provide a composition useful for personal care, pharmaceutical or cosmetic applications, having low irritation due to the absence of surface-active agents that lower the surface tension between immiscible phases.
Applicants have discovered methods of forming stable, homogeneous compositions comprising both polar and apolar fractions of natural product extracts. The applicants have now discovered that aqueous or aqueous/glycolic extracts can be successfully mixed with apolar extracts (e.g. silicone extracts) using high pressure, high shear processing to produce a single, stable homogeneous system that contains the entire complement of polar and apolar fractions from a selected natural product.
The invention is directed to stable, homogeneous dispersions comprising a water-soluble natural product extract and an oil soluble natural product extract. In certain embodiments, the dispersion does not comprise a surface active agent.
In one embodiment, the invention is directed to stable, homogeneous dispersions comprising a first composition which contains one or more polar solvents and water (or polar solvent) soluble components of a first natural product; and a second composition comprising one or more apolar solvents and oil (or apolar solvent) soluble organic components of a second natural product. Optionally, the dispersion may also comprise from about 0.01 to 8% by weight of a non-surface active lipid phosphate or a surface active agent.
In preferred embodiments, the invention is directed to stable, homogeneous dispersions comprising
(a) from about 20 to 90% by weight of a first composition comprising:
(i) about 60-95% by weight of a first polar solvent;
(ii) about 0-40% by weight of one or more second polar solvents; and
(iii) water soluble components of a first natural product; and
(b) from about 10 to 60% by weight of a second composition comprising:
(i) one or more apolar solvents; and
(ii) oil soluble organic components of a second natural product; and
(c) from about 0.01 to 8% by weight of a non-surface active lipid phosphate or a surface active agent.
In particular embodiments, the first polar solvent may be water and the second polar solvent is selected from the group consisting of water; a mono, di, tri or polyhydroxy alkyl derivative; a mono, di, tri or polyhalogenated alkyl derivative; a mono, di, tri or poly alkyl ether derivative; and a mono, di, tri or poly carboxyl alkyl derivative. The apolar solvent may be one or more of an oil (such as a vegetable oil); a mono, di, tri or polyalkyl ester or ether of a mono, di, tri or polyhydroxy compound; a saturated, unsaturated, linear, branched, or cyclic hydrocarbon; a saturated, unsaturated, linear or branched C8 to C30 fatty acid; a branched, linear, or cyclical silicone or silicone derivative; or a homopolymer or heteropolymer fluid formed by the polymerization of alkylene oxide monomers.
The dispersion may comprise components from any of the natural products which are known to contain physiological properties. Examplary natural products are mulberry, lavender, licorice root, arnica, eyebright and grape root. The invention contemplates the use of water and oil soluble components of natural products which may be obtained by any of the methods known to those skilled in the art.
The invention is also directed to methods of forming the dispersions of the invention. In one embodiment, the process includes the steps of obtaining a first natural product extract comprising a polar solvent and water based components of a natural product; obtaining a second natural product extract comprising an apolar solvent and oil soluble components of a natural product; combining the first and second extracts to form a composition; optionally adding about 0.01 to 8% by weight of a non-surface active lipid phosphate or a surface active agent; and subjecting said mixture to high pressure high shear processing to form a stable, homogeneous dispersion.
Preferred rates of high pressure, high shear processing are at a pressure of about 11,000 to about 27,000 psi, and at a shear rate which is sufficient to form a dispersion having an average particle size of from about 200 to about 1,000 nm.